The construction of the Three Gorges Project and the control of floods in the Yangtze River are the century-old dream of the Chinese nation. In 1919, Mr. Sun Yat-sen put forward the grand vision of developing the Three Gorges. After the founding of New China, Mao Zedong and other previous party and state leaders attached great importance to and cared about the demonstration work of the Three Gorges Project. After half a century of investigation, design, and planning demonstration, the National People's Congress passed the "Resolution on the Construction of the Three Gorges Project on the Yangtze River" in April 1992.
The Three Gorges Project is a key backbone project for the governance and development of the Yangtze River. It consists of three major parts: the hub project, the resettlement project, and the power transmission and transformation project. The Three Gorges Project is the largest water conservancy project in the world today, with huge comprehensive benefits such as flood control, power generation, shipping, and water resources utilization. The dam site of the Three Gorges Project is located in the Xiling Gorge section of the mainstream of the Yangtze River and in Sandouping Town, Yichang City, Hubei Province, with a controlled drainage area of approximately 1 million square kilometers.
The hub project is Ⅰ and other projects, which are composed of barrage dams, power station buildings, navigable buildings, and Maoping Creek protection projects. The water-tight buildings are designed according to the once-in-a-millennium flood, with a peak flow of 98,800 cubic meters per second; the flood check is increased by 10% based on once-a-year occurrences, and the peak peak flow is 124,300 cubic meters per second. The seismic design intensity of major buildings is Ⅶ.
The barrage dam is a concrete gravity dam. The total length of the dam axis is 2309.5 meters, the elevation of the dam top is 185 meters, and the maximum height of the dam is 181 meters. The normal storage level of the reservoir is 175 meters and the corresponding storage capacity is 39.3 billion cubic meters. The flood level in the flood season is limited to 145 meters, and the flood storage capacity is 22.15 billion cubic meters.
The power station building consists of a dam-type power station, an underground power station and a power station. Behind the dam, 26 units of 700,000 kilowatts hydropower generating units are installed with an installed capacity of 18.2 million kilowatts; underground power stations are equipped with 6 700,000 kilowatts hydropower generating units, with an installed capacity of 4.2 million kilowatts; and two 50,000-kilowatt hydropower stations are installed in the power station. The generating unit has an installed capacity of 100,000 kilowatts. The total installed capacity of the power station is 22.5 million kilowatts, and the average annual generation capacity is 88.8 billion kilowatt hours.
The navigable buildings consist of ship locks and vertical ship lifts. The ship lock is a double-line five-level continuous ship lock with a total length of 1,621 meters. The effective size of a single lock chamber is 280 meters long, 34 meters wide, and the minimum threshold water depth is 5 meters. The annual unidirectional design capacity is 50 million tons. The maximum lifting height of the shiplift is 113 meters, the effective size of the carrier is 120 meters in length, 18 meters in width, and 3.5 meters in water depth. The maximum size of the ship is 3,000 tons.
The Maoping Creek protection project includes Maoping Creek protection dams and drainage structures. The Maopingxi protective dam is an asphalt concrete core wall earth-rock dam. The axis of the dam is 889 meters long, the elevation of the dam top is 185 meters, and the maximum dam height is 104 meters. The drainage structure consists of a drainage tunnel and a drainage box culvert, with a total length of 3104 meters.
The power transmission and transformation project undertakes the important task of sending out 22.5 million kilowatts of power from all units of the Three Gorges Power Station, and has the ability to transmit power to central, eastern and Guangdong power grids. The final built scale is: 500 kV AC substation with a total capacity of 22.75 million kVA, 7280 km of AC transmission lines (converted to a single circuit length); ± 500 kV DC commutation total capacity of 24 million kilowatts, and DC transmission lines 4913 Kilometers (equivalent to the length of a single loop); corresponding dispatching automation systems and communication systems.
The resettlement project involves Hubei Province, 19 districts and counties of Chongqing City, and Chongqing's main urban area. A total of 1.3103 million urban and rural migrants have been relocated (1.2964 million in the reservoir area and 13,900 in the dam area), of which 196,200 have been resettled. Shanghai, Jiangsu, Zhejiang, Anhui, Fujian, Jiangxi, Shandong, Hubei, Hunan, Guangdong, Sichuan, Chongqing and other 12 provinces (municipalities). Rehabilitation of various types of houses in the reservoir area was 50.547 million square meters, 2 cities were relocated, 10 counties were located, 106 market towns were relocated, 1,632 industrial and mining enterprises were relocated, and professional projects were rebuilt, cultural relics protection, ecological environmental protection, reservoir bottom cleaning and geology Disaster prevention, high cut slope protection, etc.
The construction of the Three Gorges Project began in January 1993. Until October 2008, all units on the right bank power station were put into production and power generation. After 16 years of hard work, in addition to the approval of the delayed construction of the shiplift, the preliminary design and construction tasks were completed one year in advance.